Huge amounts of water and fertilizer are utilized across agricultural and landscaping practices. These practices, although readily accepted and necessary, lead to an exacerbation of water quantity and quality issues across the world. For example, agriculture uses about 70% of accessible freshwater. Water that is not used may be contaminated by toxic chemicals found in pesticides and fertilizers. Specifically, contamination of municipal water supplies by nitrates is harmful to human health and increased phosphate content in rivers and streams leads to lower oxygen levels limiting survival of fish and other aquatic life.
Rhizobia are bacteria capable of forming a symbiotic association with the roots of plants. Rhizobia benefit the host plant by fixing atmospheric nitrogen into a more readily available form to the host plant. This fixing of atmospheric nitrogen is especially important for areas where crops are grown and harvested year after year as the nitrogen naturally found in the soil is systematically depleted or limited. Rhizobia thus reduce the need for nitrogen fertilizers to be applied to new crop plantings after the previous crop has been harvested. Rhizobia have further been shown to increase plant growth and yield.
Mycorrhizal fungi form symbiotic associations with the roots of plants. Mycorrhizal fungi are known to be associated with greater than 90% of all land plants including crops, grasses and trees. Mycorrhizal fungi provide many important benefits to plants including enhanced absorption of water and nutrients from the soil, increased drought tolerance, increased pathogen resistance and protection, enhanced plant health and vigor, minimized effects of external stress, and enhanced seedling growth. In turn, the external application of Mycorrhizal fungi to plants can lead to less irrigation and fertilization, which conserves water and reduces the amount of chemicals, such as nitrates and phosphorus, and essential micronutrients. Mycorrhizal fungi are most effective when introduced to the soil prior to seed germination or at early stages of plant root proliferation.
Currently, Rhizobia is most readily available as an aqueous inoculant in sterile pouches that must be stored cold at 5° C. Prior to application to the field, the Rhizobia inoculant is conveniently formulated on to peat granules while being blended in a blending equipment such as a Munson mixer, a Marion mixer or any other suitable mixing equipment. Blending of the granules may result in attrition leading to loss of integrity. This application process has proved somewhat successful; however, the cost of granules is high and the granules have an in-consistent nature. Further, due to the difference in formulation types and granule types used to apply Rhizobia and Mycorrhizae these two beneficial products are often applied inconsistently leading to less than ideal results.
Biodac® (Biodac is a registered trademark of Kadent Gran Tek Inc.) is a 100% biodegradable granule. Further, Biodac® is low cost, readily available, resistant to attrition due to mixing and has a neutral pH. Biodac® is available in several size grades from 4/10 mesh down to 20/50 mesh all of which are classified as an exempt inert material by the U.S. Environmental Protection Agency. However, to date, only pesticides have been successfully combined with Biodac® granules.
Accordingly, there is a need in the art for Rhizobia granular formulations that are stable and available. Further, there is a need in the art for stable and homogenous mixtures of Mycorrhizae granules and Rhizobia granules.